Electrical welding apparatus.



1 No. 847,746. PATENTED MAR. 19, 1907.

T. A. EDISON.

ELECTRICAL WELDING APPARATUS.

APPLICATION FILED JULY 21, 1904.

6 SHEETS-SHBET l.

Witnesses: AI E (g Inventor 2 261M M m Attorney T. A. EDISON.

ELEGTRIOAL WELDING APPARATUS.

APPLICATION FILED JULY 21. 1904.

PATENTED MAR. 19, 1907.

s SHEETS-SHEET z.

Inventor f4, M

Attorney PATENTED MAR. 19, 1907:.

T. A. EDISON. ELECTRICAL WELDING APPARATUS.

APPLICATION FILED JULY 21,1904.

6 SHEETS-SHEET 3.

.r. w n e v m JW IV A Witnesses:

Attorney N0. 847,746. PATENTED MAR. 19, 1907.

T. A. EDISON. ELECTRICAL WELDING APPARATUS.

APPLICATION FILED JULY 2 1, 190"" M HI A. l mm QM A Sm W A \N A A Q Q Am ss Ven tor Attorney Witnesses PATENTED MAR. 19, 1907.

T. A. EDISON. ELECTRICAL WELDING APPARATUS.

APPLICATION FILED JULY 21, 1904.

6 SHBETS SHBET 5.

lin

MMM4 J Witnesses Inventor Attorney WW6? WW2 PATENTED MAR. 19, 1907.

T. AAEDISON. ELECTRICAL WELDING APPARATUS.

APPLICATION FILED JULY 21, 1904.

6 SHEETS-SHEET 6.

Inventor Attorney Witn esses UNITED STATES PATENT OFFICE.

THOMAS A. EDISON, OF ORANGE, NEW JERSEY.

ELECTRICAL WELDING APPARATUS..

Specification of Letters Patent.

Patented March 19, 1907.

Application filedJn ly 21,1904. Serial No. 217,538.

To all whom it may concern:

Be it known that I, THOMAS A. EmsoN, residing at Llewellyn Park, Orange, in the county of Essex and State of New Jersey, have invented a certain .new and useful Electrical Welding Apparatus, of which the following is a description.

My invention relates to valious new and useful improvements in electrical welding apparatus, and particularly'to apparatus of the type in which the welding is performed by the heat of an electric arc.

The improved apparatus is adapted for use in welding together the contiguous surfaces of seams of various forms, and where the seams to be welded are reproduced in the successive is especially suited for this purpose, because it has been found very difficult to make a solder. that is absolutely unaffected by electrolysis in an alkaline solution. By welding the seam between the cover and the can an I absolutely perfect joint is secured, doing away completely with the necessity for solder, and since the weld is practically superficial and extends below the surface only a fraction of an inch the cover can be removed, if necessary,-by merely filing off the top edges, thus removing the welded portions. The depth of the flange presented by the covers of my batteries is sufficient to enable five or six successive Welding operations to be'eflected, which would be much more than would ever be necessary in the life of any cell. Since the seams to be welded in my improved batteries are the same in form for the different-size cans, it is possible to perform the welding operation thereon substantially automatic-,

ally, as explained, and to facilitate the operation I find it possible to perform awelding operation on two cans simultaneously.

.There is of course no electrolytic action between the cover and the can, since they are both formed of the same metal, and conse- 5' 5i,quently the joint obtained by welding is entirely permanent.

The objects of my invention are, first, to provide an apparatus for the purpose in which a perfect and uniform welding operation may be effected, so that the resulting joint will not only be entirely gas-tight and liquid-tight, but the appearance of the joint will be entirely satisfactory; second, to provide an apparatus wherein the arc will be automatically caused to follow the seam regardless of the form of the latter; third, to provide an apparatus in which a plurality of welding operations may be performed simul-' taneously on the seams of separate articles, and, finally, to provide an apparatus in which the adjustment of the carbon orcarbons may be readily effected without interfering in any way with the operation of the device.

In order that the invention may be better (I understood, I will describe it in connection with an apparatus which has been actually installed for use in connection with the welding simultaneously of the joints of two storage-battery cans and from which its ap lication to the welding of other objects wil be understood by those skilled in the art.

In the drawings, Figure 1 is a planview of the apparatus; Fig.2, a front elevation;--.

Fig. 3 an enlarged crosssectional view on the line 3 3 of Fig. 1 Fig. 4, a similar view on the line 4 4 of Fig. 1; Fig. 5, a similar view on the line '5 5 of Fig. 4; Fig. 6, a similar view on the line 6.6 of Fig. 4; Fig.7, a horizontal sec tional View on theline 7 7 of Fig. 4; Fig. 8, an

enlarged verticalsectional view on the line 8 8 of Fig. 2 Fig. 9, a sectional view taken at right angles on the line 9 9 of Fig. 8; Fig. 10,'

a cross-sectional view on the line 10 10 of Fig. 8; Fig. 11 a similar view on the line 11 11 of Fig.8 Flg, 12, a plan view showing one side of, the burner-shield and burners with the can in position and illustrating also one of the buriier-actuators; Fig. 13, a cross-sectional view on the line 13 13 of Fig. 12; and Figs. 14, 15, and 16 detail cross-sectional views on the lines 14 14, 15 15, and 16 16, respectively, of Fig. 12. e

In all of the above views corresponding parts are'representediby the same numerals of reference.

The machine is provided with a cast-metal base '1, having cut-away portions 2, through which the cans project. Each can is carried on a platen 3, having two guide-blocks 4 4, (see Fig. 3,) so that by engaging the can against these blocks it will be properly alined.

Each platenis providedwith a screw 5pm- 'scribe corresponding paths.

jeeting downwardly from the same, engaging which is a nut 6, supported by a bracket 7. (See l ig. 2.) from the under side of the table 8, on which the base 1 is mounted. At their upper ends the cans are clamped against the fixed angular plates 84, which are secured to the standards 85, applied to the body 1, so that the inner edges of the said plates overhang the cut-away portions 2. (Sec l 3 and 13.) The means for clamping the cans against the said plates 84 consist of angular locking-plates 86, which engage the can-at its upper end. These plates 86 are rigidly secured to the angular members 10, and t he latter are locked in the desired position in any suitable way. By this arrrangement I readily accommodate cans vary ing in width, but all of the same height and length, as is the case with my improved storage battery as now manufactured. It will be understood, of course, that any other appropriate means may be employed for holding the articles rigidly in position during the welding operation. \Vith the apparatus under description provision is made for simultaneously welding two cans, and to effect this result the two carbons are carried by a frame and are guided to follow two seams by means of a pattern corresponding with the form and size of the seam somewhat like a paiitograph. This arrangement is more clearly shown in Figs. 1 to 6, inclusive. The base 1 is formed with an integral hollow box-bed 1 1 at its rear end, upon which is mounted a block 12 in guides, (see Mg. 6,) so as to be ca able only of reciprocating movemems in the same plane. A cross-arm 14 (see ligs. 1 and 6) is carried by the block 12, and pivoted to the ends of the crossarms are two links 15 15, whose forward ends are pivoted at 16 16 (see lig. 2) to a light skeleton bridge 17, made, preferably, of tubing, as shown. Obviously by such an arrangement the two ends of the bridge 17, at which the carbons are carried, as will be explained, will be caused to trans- The bridge carrying the carbons is caused to be properly moved, so that the carbons will follow the lines of. the seams by means of a pattern of the proper form to represent the seam under process of welding. This pattern 18 (see big. 4) is formed with a groove 19 therein, which is the same shape and size as the seam, and engaging said groove is a small roller 20 on the lower end of the shaft 21. On this shaft is mounted a pinion 22, engaging a rack 23, extending all around the groove 19. (See l ig. 7.) The shaft-21 is mounted in a yoke 24, carried by an arm 25, whose rear end is provided with a yoke 26, pivoted on a stationary pin 27. (See l ig. 6.) Rotatablv mounted on this pin is a double-grooved main driving-pulley 28, having a worm 29 These brackets are carried f guide-roller 20 along the groove 19.

drives a shaft 31, extending parallel with the arm 25, and at its forward end provided with a worm 32, engaging a worm-gear 33 on the shaft 21. Obviously by applying power to the main driving-pulley 28 the shaft 21 will be ver slowly rotated en a in the :inionf .1 l h h T 22 with the rack 23 and slowly moving the In or der to properly support the bridge 17, 1 provide extensions 34 at the ends, (see rigs. 1 and 2,) carr .ing shoes 35,which rest upon sta;ionar \j tables 36. If desired, a shield 257 may be employed, carried by pedestals 38 above the pattern 18, so as to exclude dus, and dirt therefrom, said shield being ob viously provided with a slot correspoiuling \Vlill the pattern-groove 19 and in which the shaft 21 travels. The carbons are carried from the bridge 17 in any suitable way. l find, however, that the best results are secured when each carbon is rotated at a relatively high speed about its center as an axis, since by doing this the are is more perfectly localized s.) as to accurately follow the sean'i. If, on the other hand, the carbons were not rota-ied, -.he arc would be more or less imperfect and would result in the jlliNlUOtlOll of an imicrfect weld.

I illustrate in the drawings satisfactory mechanism for supporting, rotating, and adjusting each carbon, re'l'erence being had particularly to Figs. 8 to 11., inclusive. Here the long carbon 39 of small diameter is supported by a sleeve 40, the latter being free to move up and down in a bearing 41, formed as part of the bridge. At its lower end the sleeve 40 is split (see Fig. 9) and on its exterior is threaded, with which portion engages a cap 42, by which the sleeve will be clamped upon the carbon in a well-known manner. The carbon is rapidly rotated by a pulley 43, having a pin 44, which engages a slot (see Fig. 9) in the sleeve, whereby the sleeve and carbon may be moved vertical y, while at the same time they are rotated by the pulley 43. Both of the pulleys 43 are driven by a belt 46 passing around them and over an idler 47 and thence to the driving-pulley 28. The idler-47 is mounted on a block 48 (see Fig. 5) in order that it maybe adjusted horizontally, so as to take up any slackin the belt 46. Refer-ring again to the carbons, I have found that although the carbons may be adjusted automatically to maintain the arc substantially constant this cannot be done except at a sacrifice of certainty of operation and the employment of complicated devices. For these reasons I prefer to adjust the carbons manually by'sonie such arrangement as that illustrated and which I now describe. Near its lower end the carbon-tube 40 is formed with a shoulder 49, with which engages a swivel 50, whereby the carbon-tube may be rotated independently of said swivel. Se-

engaging a worm-gear 30. This worm-gear cured within the swivel 50 is a yoke 51, the

and which engage a stationary" threaded sleeve 52, which surrounds the carbon-tube and which is made fast to the bridge 17. viously by rotating the yoke around the stationary threaded sleeve 52 the carbon will be elevated or depressed. This is effected by employing a second yoke, whose arms 53 lie between those of the yoke 51, and which at their upper ends are connected to a pulley 54, so that by rotating the latter the yoke 51 will be rotated with respect to the threaded sleeve 52 and the two yokes'will be moved relatively to each other telescopically, as will be understood. In order to rotate each of the pulleys-54 for regulating each carbon, I

ently rotatable with .respect to,the' controller 58 for operating the rheostat 90 for each carbon. Carried by the shaft 57 is a small milled adjusting-wheel 59, connected with a pulley 60, over which runs a belt 61 to a pulley 62 at the oints between the links and 56.v The pulley 62 is connected with a a second pulley 63, over which-runs a belt 64 to the pulley 54, so that obviously by rotating the adjusting-wheel 59 either carbon may be raised or lowered, as may be desired. At the same time the carbon-controlling mechanism is independent of the rheostat', although the adjusting-wheel 59 is located adjacent to the controller 58, so that the operator may control either of these elements by one hand.

The entire apparatus is 'sufliciently compact as to enable the two adjusting-wheels 59 and controllers 58 to be readily operated by a single operator sitting in front of the apparatus andviewing the two arcs simultaneously, as I shall describe. This is done b employing a main sight-opening 65, (see Fig. 4), in which is mounted a prism 66, (see Fig. 2,) whose facets are arranged opposite openings 67 of the tubes 68. At theirends the tubes 68 are provided with enlargements 69, (see Fig. 3,) in which are mounted prisms 70.

(See Fig. 2.) Leading down from the prisms 70 are sight-tubes 71, at the lower ends of which is mounted a rism or mirror 72 opposite the carbon and 1nto which the are is reflected. Consequently in the main sighttube 65 the two arcs may be observed, and they may be kept in their proper position and condition by manipulating either the controller-handle 58 or'the adjusting-wheel 59..

Since the sighting devices are carried by the bridge, obviously the relation between each carbon and the adjacent prisms 72 does not change as the carbon follows the seam to be welded.

In practice I find that a su erior welding operation is performed when t e metal is in-' dependently heated, since in this way the track or guide 74 will always when released.

there is a tendency of the arc to partly oxidize the metal, which sometimes results in making a poor joint. Consequently with the ap aratus in its preferred form I arrange for indbpendent heating of the metal adjacent to the seams, and I preferably construct the device so that this independent heating will progress substantially concurrei'itly and coincidently with the travel of the are. To do this most effectively, I prefer to make use of a separate gas-burner movable with the carbon' along each side of the can or article to be welded, and each burner is automatically ignited and extinguished as it commences and ends its particular path of movement. Thus, referring particularly to Figs. 12 to 16, inclusive, I. arrange guides or tracks 73, we tending parallel with the stationary clamping-surfaces 9 9, and a corresponding or some- What longer track or guide 74, (see Fig. 13,) extending parallel with one of the movable clamping-surfaces 10, so that regardless of the movements of this clamping-surface the proper parallel relation thereto or carrying the burner, as will be described. Finally I employ a similar guide or track 75, which is carried with the other movable clamping-surface 10, so as to be adjustable back and forth with the same to bear the proper relation thereto at all times. These tracks 73, 74', and 75 substantially inclose the can and provide ways upon which the burners may travel to deflect the gas-flame successively onthe sides of the can adjacent to the top thereof. Four of these burners are used, one mounted on each track and of any suitable character.

For instance, each burner may comprise a I small casing 76, (see Fig. 13,) having one or more gas-vents 77 and encircling the tubular valve 78, having a vent or vents 79 there- ,in adapted to be brought into line with the vents 77 to permit gas to esca' e through the of each of the valves 78 iseflected by a lever 80, the parts beingnormallymaintained in the position shown in Fig. 13 by light springs.

(Not shown.) Normally each of the burners is maintained at its starting ositio'n by means of a spring81, which will e gradually put under tension as the burner is moved along the track with the are and which will return each burner to its starting position Several burners are automatically operated by four arms 82, mounted upon'thc bridge 17 bysupports '83. (See resent the.

Fig. 3.) These arms are so proportioned as to successively engage the levers of the 1 several burners. For instance, as shown in P Fig. 12, one of the arms has moved the burner at the right almost to its full extent andthe next arm is just engaging the lever 80 of the succeeding burner to turn on the gas, after which the arms will be moved toward the leit to thereby release the burner at the right and permit it to be returned to its normal position. ()ne. burner will be ignited from the other, because when the carbon is passing around the corner of the can gas will be. turned on at the same time at the two corresponding burners. Thus as the carbon progresses around the seam it. will be accom panied by the gas-llame impinging on the can in the immediate locality of the arc, tending to, heat the metal at that point and facilitating'the character of the welded joint, as explained, and as well reducing the work on. the arc. The clan1ping-plates 84 and 86 act as shields under which the ilame from the burners' is impinged, (see Fig. 12,) whereby dissipation of the heat is largely prevented and the same is localized upon the can as much as possible.

The current is supplied to the carbons in any suitable way, care being of course taken to properly insulate the parts, so that the arc shall be properly formed between the carbons and the tops of the cans. For cutting oil the current whenever desired I illustrate a switch S7,(see Fig. 2,) which may be operated by the foot.

The operation of the device will be readily understood from the roregoing description. The two cans are placed on the platens 3 3, alined by the stops 4 4 and clamped between the faces 9 and 10. Power being applied to the main driving-pulley 28, the shart 21 will be slowly rotated to cause its lower end to follow the pattern-groove 19. This movement carries the two carbons simultaneously along the paths presented by the seams of both cans. In this movement the gas-burners will be successively carried along with the carbons, so as to locally heat the metals, as explained. The are is formed between the carbons and the can-tops to peri'orm the welding operation, each carbon being rapidly rotated, so as to cause the arc to accmately follow the line presented by the seam. The operator observes the two arcs through the sight-tube and properly regulates them by means of the controllers. As soon as the joint has been completely welded the circuit is broken, the cans are removed, new cans are placed in position, and the operations described are repeated.

Having now described my invention, what I claim as new therein, and desire to secure by Letters Patent, is as Follows:

1. Apparatus or welding metallic articles contiguous to a seam thereon, and comprising a carbon operatively mounted in the proper relation to establish an arc between the carbon and the article, and means for rapidly rotating the carbon about its center as an axis, as and for the purposes set forth.

2. Apparatus for welding metallic articles contiguous to a seamthereon, and compris- :ing a carbon operatively mounted in the proper relation to establish an are between the carbon and the article, means for rotating said carbon about its center as an axis, and means for independently adjusting the carbon toward and away from the article, substantially as set forth.

3. Apparatus for welding metallic articles contiguous to a seam thereon, comprising a lixed articlc-support acarbon opcratively mounted in the proper relation to establish an are between the carbon and the article, and means for automatically causing the carbon to move along a closed non-circular path, as and for the purposes set forth.

4. Apparatus for welding metallic articles contiguous to a seam thereon, comprising a carbon opcratively mounted in the proper re- .ation to establish an are between the carbon and the article, means for progressively moving the carbon with respect to the article and means for rapidly rotating the carbon about its center as an axis as it progresses, as and For the purposes set forth.

5. Apparatus for welding metallic articles contiguous to a seam thereon, coi'nprising carbon and article supports capable of relative movement with respect to each other, a carbon mounted in its support in the proper :elation to establish an are between the carbon and the article and means for independently heating the article in advance of the are, substantially as set forth.

6. Apparatus for welding metallic articles contiguous to a seam thereon, comprising a carbon operatively mounted in the proper relation to establish an arc between the carbon and the article, means for rapidly rotating the carbon, and means for independently heating the article in the locality of the are, as and For the purposes set forth.

.7. Apparatus for welding metallic articles contiguous to a seam thereon, comprising a carbon operatively mounted in the proper relation to establish an are between the carbon and the article, means for automatically causing the carbon to progress along the line ol" the seam, and means for independently heating the article progressively with the travel of the carbon, substantially as set forth.

8. Apparatus for welding metallic articles contiguous to a scam thereon, comprising a carbon operatively mounted in the proper relation to establish an are between the carbon and the article, means for progressing the c on along the ne o the seam, means For rapidly rotatinglhe carbon, and means for independently heating the article progressing carbon carried thereby movable a ong the line of the seam, and a pattern by which the support is guided to cause the carbon to follow the seam, substantially as set forth.

' 10. Apparatus for weldin the metal contiguous to a seam in a meta lic article, comprising in combination a carbon-support, a

' ports for the objects, a plurality of carbons carbon carried thereby. movable along the line of the seam, a pattern by which the support is guided to cause the carbon to follow the seam, and means for automatically moving the support along the line of the pattern to cause the carbon to follow the line of the seam, substantially as set forth.

11. Apparatus for weldin the metal contiguous to a seam in a meta lie article, comprising in combination a carbon-support, a carbon carried thereby movable along the line of the seam, a pattern by which'the sup port is guided to cause the carbon to follow the seam, and means for rotating the carbon during its travel; substantially as set forth.

12. Apparatus for welding the metal contiguous to a seam in a metallic article, comprising in combination a carbon-support, a carbon carried thereby movable along the line of the seam, a pattern with which the support engages, means for automatically moving the support along the line of the pattern to cause the carbon to follow the line of the seam, and

means for rotating the carbon travel, substantially as set forth.

13. Apparatus for simultaneously welding the metal contiguous to theseams of a plurality of metallic objects, comprising supports for the objects, a plurality of carbons mounted in the proper relation to the objects to establish an are between each. carbon and the adjacent object, a common support for the carbons and means for moving the support, whereby the carbons will simultaneously progress along the line of the seams presented by the several objects, substantially as set forth.

14. Apparatus for simultaneously welding the metal-contiguous to the seams of a plurality of metallic objects, comprising supduring its mountedin the proper relation to the objects to establish an are between each carbon and the adjacent object, a common support for the carbons and means for automatically p moving the carbon-support, so as to cause the carbons to progress along the line of the seams, substantially as set forth.

15. Apparatus for simultaneously welding the metal contiguous to the'seams of a plurality of metallic objects, comprising supports for the objects, a plurality of carbons mounted in the proper relation to the objects to establish an are between each carbon and the adjacent object, a common support for the carbons and means for simultaneously rotating the carbons about their centers as axes, substantially as set forth.

16. Apparatus for simultaneously welding the metal contiguous to the seams of a plurality of metallic objects, comprising supports for the objects, a plurality of carbons mounted in the proper relation to the objects to es tablish an are between each carbon and the adjacent object, a common'support for the carbons, means for automatically moving the carbon-support so as to cause the carbons to progress. along the line of the seams, and means for simultaneously rotating the carbons, substantially as set forth.

17. Apparatus for the purpose described,

comprising in combination, a bridge or support, pantographic connections for simultaneously causing the ends of the bridge to follow the same paths, a "carbon mounted at each end of the bridge, and a patternby which the bridge is guided, substantially as described.

18. Apparatus for the purpose described, comprising in combination a bridge or support, pantographic connections for simultaneously causing the ends of the bridge to follow the same aths, a carbon mounted at each end of tie bridge and a pattern by which the bridge is guided, and means forsimultaneously rotating the two carbons, substantially as set forth. 7

, 19. Apparatus for the purpose described, comprising in combination a bridge or support, pantographic connections for simultaneously causing the ends of the bridge to follow the same paths, a carbon mounted at each end of the bridge, a pattern by which the bridge is guided, and means for independently adjusting'the two carbons, substanti ally as set forth. r

20. Apparatus for the purpose described, comprising in combination a bridge or support, pantographic connections for simultaneously moving its two ends inthe same paths, a carbon at each end of' the bridge or support, a pattern, a rack surrounding the pattern, and a pinion carried by the bridge and engaging the said rack whereby the bridge is caused to follow the line of the pattern, substantially as set forth.

'21. Apparatus for the purpose described, 7

comprising in combination a bridge or sup- I port, a shoe carried by the bridge or support on each end, a fixed table withwhich each shoe engages for supporting the bridge, pantographic connections with the bridge, and two carbons carried by the bridge, substantially as set forth.

22. .Apparatus for'the purpose described,

comprising in combination a bridge or support,a pair of carbons carried at the ends of the bridge or support, and means for simultaneously observing the arcs formed by the two carbons, as and tor the purposes set torth.

23. Apparatus for the purpose described,

24. Apparatus for the purpose described,

comprising in combination a bridge or sup port, a pair of carbons at the end of the bridge or support, a sighting device leading from the center of the bridge or support to points adjacent to the carbons whereby the arcs formed thereby may be simultaneously ob served, and means for independently regulating the carbons, substantially as set forth.

25. In apparatus for welding the metal contiguous to the seam of metallic articles, the combination with the carbon arranged in the proper relation with the article to establish an are between the carbon and the article, and a gas-burner movable with the earbon to heat the metal contiguous to the arc,

' substantially as set forth.

26. In apparatus for welding the metal contiguous to the seam of metallic articles, the combination with the carbon arranged in proper relation with the article to establish an are between the carbon and the article, a gas-burner movable with the carbon to heat the metal contiguous to the arc, and a shield under which the burner travels, substantially as described.

27. Apparatus for welding the/metal contiguous to the seam of a hollow metallic artil cle, comprising a series oi gas-burners movable successively along the sides of the articles, and a carbon movable along the line oi" the seam, and arranged to engage the burners to cause them to follow the carbon, whereby the metal of the article will be heated locally as the arc progresses along the seam, substantially as set forth.

28. Apparatus for welding the metal contiguous to the seam of a hollow metallic article, comprising a series of gas-burners movable successively along the sides of the articles, a carbon movable along the line of the seam and arranged to engage the burners to cause them to follow the carbon, whereby the metal of the article will be heated locally as the are progresses along the seam, the connections being such that when l l l l the actuating devices engage each burner successively, the gas will be turned on within the same, substantially as set forth.

29. In an apparatus for the purpose de scribed, the combination with the carbon movable along the seam, of a burner movable parallel to the seam, a connection between the carbon and the burner whereby the burner will be moved withthe carbon, and means for releasing the burner to return it to its normal position, sul.)stantially as set forth.

30. In an apparatus for the purpose described, the combination with the carbon movable along the seam, of a burner movable parallel to the seam, a connection between the carbon and the burner, whereby the burner will be moved with the carbon, means for releasing the burner to return it to its nor mal position, and means for opening the burner prior to its movement with the carbon, substantially as set forth.

3]. In an electric welding apparatus, the combination ol 'arbon and article supports capable ol relative movement with respect to each other, a carbon mounte' in its sup port in the proper relation to maintain an are between the carbon and article, and means for rotating the carbon about its center as an axis, substantially as set forth.

3L. In an electric welding. apparatus, the combination olearbon and article supports capable ol relative'movement with respect to each other, a carbon mounted in its support in the proper relation to maintain an are between the carbon and article, and means For moving one ol said supports in a closed,

non-circular path, substantially as set lorth.

33. In an electric welding apparatus, the combination of carbon and article supports capable of relative movement with respect to each other, a plurality oi carbons mounted in proper relation to maintain an are between each carbon and the article upon which it operates, a rheostat for regulating the strength 01 each are, and means adjacent each rheostat-eontroller for varying the length of the are controlled thereby, substantially as set forth.

34. ln an electric welding apparatus, the combination of carbon and article supports capable of relative movement with respect to each other, a plurality of" carbons, and a sight ing device comprising tubes leading from a point opposite each 'arbon to a common cen ter, substantially set forth.

This specification signed and witnessed this 12th day ol July, 1904.

THUS. A. EDISON Witnesses FRANK L. Dyna, ANNA R. KLEHM. 

